The incorporation of electronic devices with pneumatic tire structures yields many practical advantages. Tire electronics may include sensors and other components for obtaining information regarding various physical parameters of a tire, such as temperature, pressure, number of tire revolutions, vehicle speed, etc. Such performance information may become useful in tire monitoring and warning systems, and may even potentially be employed with feedback systems to regulate proper tire pressure levels and with vehicle performance and control systems.
Yet another potential capability offered by electronics systems integrated with tire structures corresponds to asset tracking and performance characterization for commercial vehicular applications. Commercial truck fleets, aviation crafts and earthmover/mining vehicles are all viable industries that could utilize the benefits of tire electronic systems and related information transmission. Tire sensors can determine the distance each tire in a vehicle has traveled and thus aid in maintenance planning for such commercial systems. Vehicle location and performance can be optimized for more expensive applications such as those concerning earth mining equipment. Entire fleets of vehicles could be tracked using RF tag transmission.
Certain piezoelectric materials have been utilized in various applications related to tire and wheel assemblies and other vibrational systems. For example, piezoelectric transducers can be used as sensors to measure the response to an impressed acoustic field. Piezoelectric actuators can convert an applied electric field into kinematic energy and mechanical displacement. Piezoelectric reeds and other specialized piezoelectric formations have been employed to convert mechanical vibrations from tire rotation to electrical energy for powering tire electronics assemblies.
The above applications and others employing piezoelectric materials are typically configured for operation such that the piezoelectric materials are subjected to limited levels of strain and/or electrical charge. For example, it is typically not desirable to subject a piezoelectric sensor or power generation device to such high levels of strain that the piezoelectric materials crack or break. Such an occurrence would hinder or destroy the intended functionality of the piezoelectric device and require replacement of the piezoelectric components.
In accordance with the present subject matter, piezoelectric devices are configured for use in environments where their structural integrity is intentionally jeopardized. More particularly, piezoelectric devices are configured to crack or break upon being subjected to a certain triggering condition and thus serve in combination with other circuit elements as a self-powered signaling mechanism for one-time use.